You -- your latest entertainment. From ABC news now. It is unimaginable. Parents putting their children on a train to leave their home country to save their lives. Not knowing if they would ever see them again. It was a reality for so many families during the Holocaust. A new HBO documentary. Tells the heartbreaking. Yet uplifting story about an ordinary American couple from Philadelphia who put their lives on the line. To -- -- Nazi Germany and rescue fifty children. It was a successful mission that saved these children's lives. And here's a look. To take a child from its mother seem to be the lowest thing a human being -- do. Yet it was as if we had drawn -- in the -- in -- most turbulent -- Every parent agreement seemed to stay here it gets. -- -- Take my child to a -- short. Steve Preston -- the filmmaker he joins us today along with one of the fifty children Annie Wang cart -- thank you both for being with us today we. And appreciated. Steve I wanna -- you first -- even -- about the story. Well Gilbert and Elmer Krause. This couple from Philadelphia who carried out this rescue. Were my wife's grandparents. And my wife Liz Hurley and her three cousins the four grandchildren of Gilbert and Alan or. Knew the vague outlines of this story growing up. Their grandmother -- or had actually written a manuscript some sort of a memoir of sorts. Several years after this episode in which she described what she and her husband. Had done in the spring of 1939. But nobody really knew the full details nobody knew the full scope of the story. In -- much more recently. When the family began to do -- little more research and then a few years ago after I had. Spent some time reading this unbelievable. Manuscript and -- had written. It began to not -- This was such an incredible story. That may be there -- the makings of of -- could documentary film was this a clandestine operation or had this been relatively. Well known at the time. Not relatively well known certainly but not. Not exactly ten deaths time Gilbert -- was a lawyer. Who knew that America had these very very strict immigration laws with strict -- with strict opponents. And he knew he had to figure out a legal way to bring children into this country so he worked openly with members of the State Department. And with consulate. And American officials who were both in Berlin and Vienna. -- wasn't a top secret mission and in fact the -- knew all about it. There were no secrets on that and but it was. Also not a widely known mission. And that's mostly because. Neither Gilbert -- -- Krause really wanted to draw too much attention to themselves and what and when they were doing. In the hopes that possibly. This would lead ultimately to other rescue missions as well which unfortunately did not happen. And in -- year one of the subjects in this documentary how old were you time and time you were ten years old at the time. And subsequently what happened to your parents and they eventually. Was me and my sister who arrived in this country the day the war broke September 1 1930 men. At the time at ten years old at such a young age what was going through your mind. When. Unfortunately there was a mistake made. With me which is -- -- -- on the kids schools some of them were really weighing down. Just to make a decision. But for some reason. We went -- so -- I had to make the decision. That if they've tried to influence me. My parents inclusive place for this to -- him I was not going and this time made the decision. -- just go and yet so you know. And I was filled with shame. The times a minute. They said. We'll take her and who -- going. And I didn't say that consisted you have a week to just. And all that time. I knew -- about myself that I was willing to abandon my pants and my sister and saved my own life. When you look now this documentary. What goes through your mind when you think about the weight of that decision that you had to make at such a young -- same thing -- haven't changed. You can't achieve it froze right there. Steve were you able to get a hold he fifty children is obviously the title of them. Along with -- how many of -- children where -- -- to get ahold of. There are 99. Have surviving children who appear in the film fortunately I was able to reach several others. Close to half of the children I was ultimately able to locate. You know it's hard to keep track. Fifty people 75 years later names change women's names -- But fortunately I was able to reach a number of them. And was able to take advantage of their wonderful memories. Family photographs that are in the film. There was just it was very fulfilling certainly from me to be able to meet wonderful people like -- some of the other rescue children into. Hear their stories and also to share with them a little more information about the Krause is as well after all these years. It's an amazing story and told in such an amazing -- Steve penny thank you so much for being with us today it's called fifty children airs on HBO. April and.

This transcript has been automatically generated and may not be 100% accurate.

{"id":18908932,"title":"'50 Children' Documents Holocaust-Era Rescue Mission","duration":"6:14","description":"Documentary film about a Jewish couple from Philadelphia who saved children during the Holocaust.","section":"Entertainment","mediaType":"Default"}